JPH0532490B2

JPH0532490B2 -

Info

Publication number: JPH0532490B2
Application number: JP61293528A
Authority: JP
Inventors: Hideo Matsui; Hiroshi Fuje
Original assignee: Teijin Ltd
Current assignee: Teijin Ltd
Priority date: 1985-12-11
Filing date: 1986-12-11
Publication date: 1993-05-17
Also published as: EP0226137A2; CA1282923C; JPS62231014A; DE3682572D1; EP0226137B1; EP0226137A3; US4842796A

Description

【発明の詳細な説明】[Detailed description of the invention]

（産業上の利用分野）本発明は、従来のポリメタフエニレンイソフタ
ルラミド系繊維に比べて著しく高い強度を有する
新規なポリメタフエニレンイソフタラミド系繊
維、及び該繊維を工業的に製造する新規な方法に
関するものである。（従来技術）例えば、米国特許第3287324号、同第3300450
号、同第3560137号及び同第4073837号等に記載の
如く、ポリメタフエニレンイソフタラミド繊維は
従来公知であり、「コーネツクス」（登録商標）、
「NOMEX」（登録商標）などの商品名で市販さ
れている。この繊維は、すぐれた耐熱性と難燃性
とを有するため、その特性を発揮し得る産業用、
衣料用の各分野に使用されている。しかしながら、従来のポリメタフエニレンイソ
フタラミド繊維は、その機械的物性が未だ充分と
は云えず、特に破断時の強度が高々5.5ｇ／de程
度であるため、より高い強度が要求される分野、
例えば、ゴム補強材、樹脂補強材、バツグフイル
ター用フエルトの基材、各種ベルト等の分野への
使用が制限されている。このため、高強力全芳香族ポリアミド繊維とし
て、ポリパラフエニレンテレフタラミド繊維が製
造されているが、該繊維は製造コストが高いばか
りでなく、破断時の強度は20ｇ／de以上と非常
に大きいものの伸度は約５％以下と小さいため、
ある程度以上の伸度が要求される分野には適さな
い。また、該繊維は使用中にフイブリル化しやす
いという欠点もある。（発明の目的）本発明の第１の目的は、従来のポリメタフエニ
レンイソフタラミド繊維に比べて著しく高い強度
とタフネス（即ち、6.5ｇ／de以上の破断強度と
35以上のシルクフアクター）を有する新規なポリ
メタフエニレンイソフタラミド系繊維を提供する
ことにある。本発明の第２の目的は、上記の繊維を工業的に
製造するための新規な方法を提供することにあ
る。（発明の構成）上記の目的は、本発明に係る高強度ポリメタフ
エニレンイソフタラミド系繊維及び上記繊維製造
方法によつて達成される。即ち、本発明のポリメタフエニレンイソフタラ
ミド系繊維は、ポリマー繰返し単位の少くとも95
モル％がメタフエニレンイソフタラミドからなり
かつポリマー濃度0.5ｇ／100mlの無水Ｎ−メチル
−２−ピロリドン溶液にて30℃の温度で測定した
固有粘度［η］ｆが0.5〜2.5であるポリメタフエ
ニレンイソフタラミド系重合体からなる繊維であ
つて、0.18〜0.22の複屈折率、45〜55％の結晶化
度及び35〜45Åの結晶サイズを有することを特徴
とする破断強度6.5ｇ／de以上、シルクフアクタ
ー35以上のポリメタフエニレンイソフタラミド繊
維の製造方法である。また、本発明のポリメタフ
エニレンイソフタラミド系繊維の製造方法は、ポ
リマー繰返し単位の少くとも95モル％がメタフエ
ニレンイソフタラミドからなりかつポリマー濃度
0.5ｇ／100mlの無水Ｎ−メチル−２−ピロリドン
溶液にて30℃の温度で測定した固有粘度［η］が
0.7〜2.5であるポリメタフエニレンイソフタラミ
ド系重合体を、有機溶媒に溶解して紡糸ドープと
なし、該紡糸ドープを塩化カルシウムを含む水性
凝固浴中に押出し、水洗、膨潤延伸、乾燥、乾熱
延伸してポリメタフエニレンイソフタラミド系繊
維を製造する方法において、紡糸して得た未延伸
繊維を、(イ)第１次水洗工程に賦して繊維中の有機
溶媒含有率を15〜30重量％に調整し、(ロ)次いで第
１次水浴延伸工程に賦して繊維中の有機溶媒含有
率が15〜30重量％の状態において少くとも１段
で、1.1〜1.5倍に延伸し、(ハ)引続き第２次水洗工
程に賦して繊維中の有機溶媒含有率を15重量％未
満に調整した後、(ニ)第２次水浴延伸工程に賦して
少くとも１段にて1.1倍以上に延伸し、(ホ)次いで
乾燥し、(ヘ)しかる後乾熱延伸工程に賦して全延伸
倍率が4.0〜7.0倍となる倍率で延伸することを特
徴とする方法である。本発明の高強力ポリメタフエニレンイソフタラ
ミド系繊維は、ポリマー繰返し単位の95モル％以
上がメタフエニレンイソフタラミド単位からなり
かつその固有粘度［η］ｆが0.7〜2.5という特定
範囲内にあるポリメタフエニレンイソフタラミド
系重合体によつて構成される。そして、従来のポ
リメタフエニレンイソフタラミド繊維に比して格
段に大きな分子配向、即ち複屈折率にして 0.18〜0.22という分子配向を有し、また結晶化
度も大きくＸ線法で求められる結晶化度にして45
〜55％の範囲内にある。その反面、従来のポリメ
タフエニレンイソフタラミド繊維に比して小さな
結晶サイズを有し、Ｘ線回折から求められる結晶
サイズが35〜45Åの範囲内にある。本発明のポリメタフエニレンイソフタラミド系
繊維を構成するポリマーは、ポリメタフエニレン
イソフタラミド単独重合体であることが好ましい
が、ポリマー繰返し単位の95モル％以上、好まし
くは98モル％以上がメタフエニレンイソフタラミ
ドである重合体であればよく、５モル％以下、好
ましくは２モル％以下の第３成分を共重合したも
のでもよい。第３成分が５モル％を超えると、繊維の結晶化
度が低下し、破断強度やタフネス等の物性も悪化
する。５モル％以下の割合で共重合し得る第３成分と
しては、例えばテレフタル酸、パラフエニレンジ
アミン、メタキシリレンジアミン等があげられ
る。繊維を構成するポリメタフエニレンイソフタラ
ミド系重合体の重合度は、該重合体を脱水したＮ
−メチル−２−ピロリドンにポリマー濃度0.5
ｇ／100mlとなるように溶解し30℃で測定した固
有粘度［η］ｆにして、0.7〜2.5、好ましくは1.2
〜2.0の範囲内にある。［η］ｆが0.7未満では、
繊維の分子配向度、結晶化度、結晶サイズ等を前
述のように調整しても、破断強度及びタフネスの
大きな繊維とはならず、本発明の目的を達成し得
ない。一方、重合体の固有粘度［η］が2.5を超
えるものは、紡糸ドープの粘度が異常に高くな
り、紡糸ドープの粘度を紡糸可能な粘度の限界内
に抑えようとすると紡糸ドープのポリマー濃度を
極端に小さくしなければならず良好な生産性にて
紡糸することが不可能である。繊維を構成する上記重合体には、必要に応じ、
着色剤、紫外線吸収剤、耐光性安定剤、難燃剤等
の各種添加剤を含有してもよい。本発明のポリメタフエニレンイソフタラミド系
繊維は、0.18〜0.22好ましくは0.19〜0.21の複屈
折率を有し、このことは該繊維が非常に高度の分
子配向を有することを示す。また、該繊維は従来
のポリメタフエニレンイソフタラミド繊維に比べ
て顕著に高い結晶化度即ち45〜55％好ましくは48
〜53の結晶化度を有し、さらに、従来のポリメタ
フエニレンイソフタラミド繊維に比べて小さい結
晶サイズ、即ち35〜45Å、好ましくは38〜43Åの
結晶サイズを有する。複屈折率が0.18未満では、繊維の結晶化度が48
％以上となり得ず、所望の破断強度、タフネス等
を有するものとはならない。一方、複屈折率が
0.22を超えると、結晶化度が55％より大となり、
繊維の伸度が低くなり繊維がもろくなる。また、
結晶化度が45％より小さいと繊維は十分な強度を
発現せず、逆に結晶化度が55％を超えると繊維の
伸度が低くなりもろい繊維となる。さらに、結晶サイズが35Åより小さいと、繊維
における結晶部と非晶部との区分が不明確となり
繊維の寸法安定性が悪くなり、結晶サイズが45Å
より大きいと、繊維内部において結晶が繊維軸の
方向に揃い難くなり、繊維物性が低下する。本発明のポリメタフエニレンイソフタラミド系
繊維において、このように高配向高結晶性にする
とともに個々の結晶の大きさを小さく制御するこ
とによつて、該繊維のもつ伸度を損うことなく、
破断時の強度が従来のポリメタフエニレンイソフ
タラミド繊維に比べて約20％以上も向上し、かつ
シルクフアクターで表わされるタフネスも増大す
ることは、全く予期し得ないことである。なお、本発明者らの研究によれば、本発明のポ
リメタフエニレンイソフタラミド系繊維は、通
常、90〜95％の結晶配向度を有し、結晶配向度も
従来の繊維に比べてかなり高くなることが判明し
た。また、本発明のポリメタフエニレンイソフタラ
ミド系繊維の形態はマルチフイラメント、ステー
プルフアイバーの何れでもよく、繊度や断面形状
も限定されないが、フイラメント当りの繊度は一
般に１〜10deの範囲が適当であり、断面形状は、
円形、だ円形、三角形、まゆ形その他任意の形状
をとることができる。上述の如き特定の微細構造に起因して、本発明
のポリメタフエニレンイソフタラミド系繊維は、
6.5ｇ／de以上、好ましくは、7.0〜8.5ｇ／deの高
い破断強度を有する。そして、このような高い破
断強度を有するにもかかわらず、本発明の繊維は
破断時の伸度が20〜30％という好適な値を有す
る。このため繊維が破断に至るまでの仕事量の目
安となるシルクフアクターは35以上となり、大き
なタフネスを示す。しかも、本発明の繊維は、耐フイブリル性にも
すぐれており、ポリパラフエニレンテレフタラミ
ド繊維のように、使用中に繊維がフイブリル化す
るという問題はない。また、耐熱性も良好であ
り、300℃における収縮率が７％以下であり、熱
に対する寸法安定性にもすぐれている。なお、本発明の繊維において、ポリマーの全末
端の20％以上がアニリン等の一官能性化合物によ
つて封鎖したポリメタフエニレンイソフタラミド
系重合体からなる繊維は特に高温時に長時間保持
した場合の強度維持率もすぐれたものとなる。上述のような本発明の高強力ポリメタフエニレ
ンイソフタラミド系繊維は、以下に述べる一連の
工程からなる本発明の方法により工業的に製造す
ることができる。即ち、まず、紡糸工程において、ポリマー繰返
し単位の95モル％以上がメタフエニレンイソフタ
ラミドでありかつ固有粘度［η］が0.7〜2.5、好
ましくは1.2〜2.0のポリメタフエニレンイソフタ
ラミド系重合体を有機溶媒に溶解した紡糸ドープ
を、少くとも１個の紡糸孔を有する紡糸口金から
押出し凝固浴中にて凝固させ末延伸繊維を形成す
る。この場合、紡糸ドープを直接凝固浴中に押出
してもよく、一たん空気中に押出した後直ちに凝
固浴中へ導入させて凝固させてもよい。一般に紡
糸ドープ中に塩化カルシウム、塩化リチウム等の
無機塩を添加すると溶解力が増大するため好まし
いと云われているが、本発明の方法では、実質的
にかかる無機塩を含まない方が好ましい。紡糸ド
ープ中に無機塩を含むと、紡糸後に繊維中に含ま
れる無機塩を洗浄除去する操作が煩雑で、繊維の
製造工程が長くかつ複雑となる。紡糸ドープ調製のために使用する有機溶媒とし
ては、極性アミド系溶媒が適当であり、なかでも
Ｎ−メチル−２−ピロリドン、Ｎ，N′−ジメチ
ルホルムアミド又はＮ，N′−ジメタルアセトア
ミドが好ましい。紡糸ドープ中のポリマー濃度
は、ポリマーの固有粘度によつても異るが一般に
15〜30重量％が好適である。一方、凝固浴は、塩化カルシウム、塩化マグネ
シウム、塩化亜鉛などの無機塩の水溶液が用いら
れる。凝固浴の温度は60〜100℃が好ましい。具
体的な紡糸条件は、例えば特公昭48−17551号、
米国特許第4073837号等に詳しく記載されている。凝固浴から引出された未延伸繊維は、次に、第
１次水洗工程において、繊維中に含まれる有機溶
媒の一部を除去し、繊維中の溶媒含有率を15〜30
重量％に調製する。なお、本発明でいう繊維中の
溶媒含有率とは、溶媒を全く含まない繊維の重量
に対する繊維中の有機溶媒の重量を百分率で表わ
した値である。この第１次水洗工程は、１個の水洗浴を使用し
て１段で実施してもよく、２個以上の水洗浴を使
用して２段以上で実施してもよい。第１次水洗工
程では、水洗浴中に紡糸ドープの有機溶媒と同じ
有機溶媒を10〜40重量％含むのが好ましく、ま
た、第１次水洗工程における水洗浴の温度は20〜
70℃が好ましい。上述の第１次水洗工程において有機溶媒含有率
を調整された繊維は、次に、第１次水浴延伸工程
において、1.1〜1.5倍の全延伸倍率に延伸され
る。この第１次水浴延伸は１段で行つてもよく、
２段以上に分けて行つてもよい。殆どの場合、こ
の第１次水浴延伸工程でも繊維中の有機溶媒の一
部が除去されるが、延伸中に有機溶媒含有率が15
重量％未満に低下しないよう延伸浴組成を調整す
る必要がある。このため、延伸浴中にドープ中の
有機溶媒と同じ有機溶媒を３〜30重量％含むのが
好ましい。また、延伸浴温度は50〜95℃、好まし
くは60〜90℃とするのが適当である。なお、第１次水浴延伸における延伸倍率は1.1
〜1.5倍とする（２段以上に分けて延伸する場合
は全延伸倍率にして1.1〜1.5倍とする）必要があ
り、この延伸倍率が1.1倍未満では、この延伸工
程の効果が乏しく、最終的に得られる延伸繊維の
結晶構造、分子配向が不十分となり、所望の強
度、タフネスを有する繊維とはなり得ない。ま
た、延伸倍率が1.5倍を超えると、第１次水浴延
伸工程で分子の流れ（フロ−）が優先し配向度の
上らない繊維となるため、この延伸工程の効果が
乏しい。好適な第１次水浴延伸工程では、第１次水洗工
程を経た繊維は、先ずドープ中の有機溶媒と同じ
有機溶媒を10〜30重量％の濃度で含む第１浴（水
浴）において50〜70℃の温度で1.1〜1.4倍に延伸
され、引続き上記有機溶媒を５〜15重量％であつ
てかつ第１浴よりも低い濃度で含む第２浴（水
浴）において70〜90℃の温度で第１次水浴延伸工
程における全延伸倍率が1.1〜1.5倍となるように
延伸される。このような延伸条件を採用すると、
第１次水浴延伸がきわめて円滑に実施され、しか
も、最終的に得られる延伸繊維の物性が特にすぐ
れたものとなるので好ましい。第１次水浴延伸工程を経た繊維は、次に、第２
次水洗工程に送られ、ここで繊維中の有機溶媒含
有率を15重量％未満に低減させる。この第２次水
洗工程も１段又は２段以上で実施することができ
る。第２次水洗工程後の繊維中の有機溶媒含有率が
15重量％以上であると、後続の第２次水浴延伸工
程で繊維の分子配向が上らず、さらに次の乾熱延
伸での結晶化が進まないため、所望の物性を有す
る繊維が得られない。第２次水洗工程は、１浴又は２浴以上の水洗浴
を用いて実施されるが、水洗浴としては水のみ、
またはドープ中の有機溶媒と同じ有機溶媒を10重
量％以下の濃度で含む水からなる浴が用いられ
る。水洗浴の温度は60〜90℃が好ましい。第２次水洗工程で有機溶媒含有率を15重量％未
満に調整された繊維は、引続き第２次水浴延伸工
程において、1.1倍以上、好ましくは1.5〜3.0倍に
少くとも１個の延伸浴を用い少くとも１段で延伸
される。第２次水浴延伸工程でも延伸中に繊維内
に残留する有機溶媒の一部または全部が除去され
る。延伸浴としては水のみ又はドープ中の有機溶
媒と同じ有機溶媒を10重量％未満の濃度で含む水
が用いられる。延伸浴温度は90〜100℃が好まし
い。第２次水浴延伸の後に、更に、水のみで繊維を
水洗して残留溶媒を完全に除去するのが好まし
い。かくして第２次水浴延伸を行ない、更に必要に
応じて水洗を施した繊維は、例えば100〜140℃の
乾燥ローラに数回巻回して乾燥した後、乾熱延伸
を行う。乾熱延伸工程では、繊維は、熱板又は加熱室中
で、紡糸後の全延伸倍率が4.0〜7.0倍、好ましく
は4.5〜6.5倍となるように延伸される。延伸温度
は300〜450℃が好ましく、この乾熱延伸工程での
延伸倍率は、1.5〜2.5倍が適当である。なお、全延伸倍率が4.0倍よりも低いと、得ら
れる繊維の破断強度が6.5ｇ／deより低くなり、
また、7.0倍より高いと、延伸中に毛羽や断糸が
発生するので好ましくない。上述の如く紡糸直後の繊維にそれぞれ特定条件
で第１次水洗工程−第１次水浴延伸工程−第２次
水洗工程−第２次水浴延伸工程（−最終水洗工程）−
乾燥工程−乾燥延伸工程を連続的又はバツチ式に
実施し、さらに必要に応じて熱処理、捲縮加工、
その他の仕上げ加工を行うことにより、良好な生
産性にて本発明の高強力ポリメタフエニレンイソ
フタラミド系繊維を製造することができる。（発明の効果）上述の如き本発明のポリメタフエニレンイソフ
タラミド系繊維は、従来のポリメタフエニレンイ
ソフタラミド繊維に比べて約20％以上も強度が大
きく、しかも十分な伸度を有し、さらに耐熱性に
も優れているため、従来ポリメタフエニレンイソ
フタラミド繊維が使用できなかつたゴム補強材、
樹脂補強材、バツグフイルター用フエルトの基材
等の分野にも使用が可能となり、また、従来のポ
リメタフエニレンイソフタラミド繊維が使用され
ていた分野でも同程度の強度の製品を製造するた
めに必要とする繊維の使用量を減らすことができ
るので、製品の軽量化、短小化等をはかることが
できる。さらに、本発明のポリメタフエニレンイソフタ
ラミド系繊維は、初期強度が高い上に、高温での
強度保持率は従来のポリメタフエニレンイソフタ
ラミド繊維と同等であるため、バツグフイルター
等の高温で常時使用される製品に使用したときに
は、製品の寿命が延長するという効果も存する。また、本発明の製造方法によれば、上述の高強
度ポリメタフエニレンイソフタラミド系繊維を安
定した工程調子で効率的に製造することができ
る。（各指標の測定法）次に、本発明でいう各指標の測定法を説明す
る。 (a) 固有粘度（［η］，［η］ｆ）固有粘度はポリマーの分子量を表わす目安とな
るもので、本発明では、無水Ｎ−メチル−２−ピ
ロリドン100mlにポリマー又は繊維0.5ｇを溶解し
た溶液の30℃における固有粘度で表わす。なお、ここでは原料ポリマーの固有粘度を
［η］、繊維とした後の固有粘度を［η］ｆとす
る。 (b) 結晶化度通常のＸ線測定法による。但し、結晶部、非晶
部の算出は、以下の通りとする。 (i) 2θの範囲は、12°から32°までとする。 (ii) 非晶部2θ＝17°から2θ＝30°まで直線を引き、
この線分と2θ＜17°，2θ＞30°の子午回折曲線と
からなる曲線を非晶散乱曲線とし、これと無配
向近似曲線との間の部分（Ｃ）が結晶の寄与、
これと空気散乱曲線との間の部分（Ａ）が非晶
の寄与とする。結晶化度＝Ｃ／Ｔ（１−12.7／100）但し、Ｔ＝Ａ＋Ｃ (c) 結晶サイズ理学電機社のＸ線発生装置（Cat.No.4032A2）、
広角回折計及び計数回路ユニツトを使用する。試
料は約2.2ｇ／cmの幅密度になるように4.5cm長の
ホルダーに装着し回折計のスキヤン軸に対して、
延伸方向（長さ方向）を垂直にする。 Cu−Kα線（λ＝1.5418Å）使用する。結晶サ
イズＤはÅ単位で次式により計算される。Ｄ＝0.94λ／（Ｂ−ｂ）cosθ （この式は広く高分子Ｘ線回折学の本に記述し
てある。） 0.94はシエラー定数と呼ばれるもの、Ｂはラジ
アン単位で表わした測定ピーク（2θ＝27.3℃）の
半価幅。ｂは装置のブロードニング定数（ラジア
ン単位）であり、上記装置の場合0.0017rad（約
0.1℃）である。ＢをＸ線回折チヤートから求めるには次の手順
による。赤道上に二つの重なつた主要ピークが存
在する場合はそれぞれのピークがガウス曲線の形
をしていると仮定して、各ピークを分離する。次
に、子午方向の回折曲線から求められる、ピーク
のない所の高さを点綴した曲線をベースラインと
して採用し、ピーク頂点とベースラインの中点よ
りベースラインに平行に直線を引き測定ピークの
交点の幅（半価値）をラジアン単位で求め、これ
をＢとする。二つの主要ピークが重なつている場合と、実質
上一つしか主要ピークが認められない場合とでは
本発明で特定したＤの範囲は異なる。二つの主要
ピークが重なつていて、2θの小さい方のピークを
ガウス曲線として取り出して測定した場合はＤは
55Å以下であるべきであり、実質上一つしか主要
ピークが認められず、そのピークからＤを計算し
た場合のは33Å以下であるべきことが分つた。二
つの場合のＤの範囲が異なる理由は、おそらく、
実質上一つしか観測されないピークも本来は二つ
のピークから成立すべきものであり、共重合効果
のため、あたかも一つのピークのみとして観測さ
れるであろう。なお、詳細な測定条件は下記の通りである。電圧 50kv 電流 80mA タイムコンスタント 1sec 掃引スピード 2°／min チヤートスピード２cm／min 試料面上の照射直径 2.8mmφ (d) 結晶配向度結晶サイズを測定したものと同一のＸ線発生装
置、広角回折計及び計数回路ユニツトを使用する
が、新たに方位角方向に測定出来る繊維回転試料
台を取りつける。サンプルの試料密度も同様であ
る。赤道線上で最大のピークを有する2θ値を保つ
たまま方位角方向に繊維を回転して配向回折ピー
クを得る。ベースラインを見い出すことは容易で
あり、このベースラインに頂点から下した垂線の
中点からベースラインに平行な直線を引きピーク
の肩との交点を求める。この交点の作る線分の長
さ（半価幅）をＨ（度）とすると配向度ｆは次式
で求められる。ｆ＝180−Ｈ／180×100（％）この方法は一般の高分子Ｘ線回折の文献に紹介
されている。なおその他の測定条件は結晶サイズの場合と同
じである。 (e) 破断時の強度、伸度 JIS Ｌ−1015（1983）の「化学繊維ステープル
の試験方法」による。 (f) シルクフアクター次式により算出する。シルクフアクター＝強度（ｇ／de）×√伸度（％） (g) 繊維中の有機溶媒含有率特公昭53−10173号公報第４欄に記載の残留溶
媒量Ｓの測定法による。 (f) 水洗浴、延伸浴中の有機溶媒濃度繊維中の有機溶媒含有率は次の手順により測定
することができる。 (1) 糸条約5grを採取し、精秤する。この重さを
W₁とする。 (2) 水分率既知の標準メタノール１にて60℃１
日間試料を抽出する。 (3) 抽出メタノールの水分をカールフイツシヤー
法で測定し、抽出させた水分をW₂とする。 (4) 抽出メタノールを蒸発乾固する（次第に高い
温度で行い、最終的には300℃とし、全体で５
時間行う）。 (5) 残渣を秤量し、この重さをW₃とする。 (6) 抽出後の試料を130℃で１時間乾燥し、秤量
する。この重さをW₄とする。 (7) 次式により残留触媒量Ｂを算出する。Ｂ＝W₁−W₂−W₃−W₄／W₄×100（％）（実施例）次に本発明の実施例及び比較例を詳述するが、
本発明はこれらにより何ら限定されるものではな
い。実施例１イソフタル酸クロライド（mp44.5〜45.0℃）
14.2ｇを金属ナトリウムにて脱水したテトラヒド
ロフラン100mlに溶解し、これを３枚の回転刃を
有するワーリングブレンダーに入れ、毎分約300
回転の攪拌を行いながらメタフエニレンジアミン
（mp62.0〜63.0℃）7.41ｇを脱水したテトラヒド
ラフラン100mlに溶解した溶液を細流として徐々
に加えていくと白濁した乳化液が得られる。攪拌
を約５分間継続した後、攪拌速度を毎分約1500回
転とした所へ炭酸ソーダ14.8ｇ及び食塩28.0ｇを
300mlの水に溶かした水溶液を速やかに加え、約
５分間攪拌を続行する。反応系は数秒後に粘度が増大し、再び低下白色
の懸濁系が得られる。静置により透明な水溶液層
が分離するので、これを取除き、濾過によつて白
色重合体16.4ｇ（収率98％）が得られた固有粘度
［η］1.45のポリメタフエニレンイソフタラミド
重合体をＮ−メチル−２−ピロリドンからなる溶
媒に20.5重量％の濃度で溶解して紡糸ドープを調
製し、この紡糸ドープを用いて特公昭48−17551
号公報に記載の湿式紡糸法に従つて、孔径0.07mm
の紡糸孔を10000個設けた紡糸口金から塩化カル
シウム濃度45％、温度90℃の塩化カルシウム水溶
液からなる凝固浴中に紡糸した。凝固した未延伸繊維は、凝固浴から引出された
段階で45重量％の溶媒を含んでいた。この未延伸繊維を、第１水洗工程において、30
重量％の溶媒を含む30℃の水浴中を通して繊維中
の溶媒含有率を25重量％に低下させた。次に、こ
の繊維を第１次水浴延伸工程において第１表に示
す条件で２段延伸した。 (Field of Industrial Application) The present invention provides a novel polymetaphenylene isophthalamide fiber that has significantly higher strength than conventional polymetaphenylene isophthalamide fibers, and a method for industrially producing the fiber. It concerns a novel method. (Prior art) For example, US Patent No. 3287324, US Patent No. 3300450
Polymetaphenylene isophthalamide fibers are conventionally known as described in No. 3560137 and No. 4073837, and are known as "Cornetx" (registered trademark),
It is commercially available under product names such as "NOMEX" (registered trademark). This fiber has excellent heat resistance and flame retardancy, so it can be used in industrial applications that can demonstrate its properties.
Used in various fields of clothing. However, the mechanical properties of conventional polymetaphenylene isophthalamide fibers are still not sufficient, and in particular, the strength at break is only about 5.5 g/de, so it is suitable for fields where higher strength is required. ,
For example, its use in fields such as rubber reinforcing materials, resin reinforcing materials, felt base materials for bag filters, and various belts is restricted. For this reason, polyparaphenylene terephthalamide fiber is produced as a highly tenacious wholly aromatic polyamide fiber, but this fiber is not only expensive to manufacture, but also has a very high strength at break of 20 g/de or more. The elongation of the large ones is small, about 5% or less, so
It is not suitable for fields that require a certain degree of elongation. Another drawback is that the fibers tend to fibrillate during use. (Objective of the Invention) The first object of the present invention is to have significantly higher strength and toughness (i.e., a breaking strength of 6.5 g/de or more) than conventional polymetaphenylene isophthalamide fibers.
An object of the present invention is to provide a novel polymetaphenylene isophthalamide fiber having a silk factor of 35 or more. A second object of the present invention is to provide a new method for industrially producing the above-mentioned fibers. (Structure of the Invention) The above object is achieved by the high-strength polymetaphenylene isophthalamide fiber and the above-described fiber manufacturing method according to the present invention. That is, the polymetaphenylene isophthalamide fiber of the present invention has at least 95 polymer repeating units.
Polymer whose mol% is metaphenylene isophthalamide and whose intrinsic viscosity [η]f is 0.5 to 2.5 when measured at a temperature of 30°C in an anhydrous N-methyl-2-pyrrolidone solution with a polymer concentration of 0.5 g/100 ml. A fiber made of a metaphenylene isophthalamide-based polymer, characterized by having a birefringence of 0.18 to 0.22, a crystallinity of 45 to 55%, and a crystal size of 35 to 45 Å, with a breaking strength of 6.5 g. /de or more and a silk factor of 35 or more. In addition, the method for producing the polymetaphenylene isophthalamide fiber of the present invention is characterized in that at least 95 mol% of the polymer repeating unit is composed of metaphenylene isophthalamide and the polymer concentration is
The intrinsic viscosity [η] measured at a temperature of 30℃ with 0.5g/100ml of anhydrous N-methyl-2-pyrrolidone solution is
A polymetaphenylene isophthalamide-based polymer having a molecular weight of 0.7 to 2.5 is dissolved in an organic solvent to make a spinning dope, and the spinning dope is extruded into an aqueous coagulation bath containing calcium chloride, washed with water, swelled and stretched, dried, In the method of producing polymetaphenylene isophthalamide fibers by dry heat drawing, the undrawn fibers obtained by spinning are subjected to (a) a first water washing step to reduce the organic solvent content in the fibers. 15 to 30% by weight, and (b) then subjected to the first water bath stretching step to increase the amount by 1.1 to 1.5 times in at least one stage when the organic solvent content in the fiber is 15 to 30% by weight. (c) Subsequently subjected to a second water washing step to adjust the organic solvent content in the fiber to less than 15% by weight, and (d) applied to a second water bath drawing step for at least one step. A method characterized by stretching the material to 1.1 times or more, (e) then drying, and (f) thereafter applying a dry heat stretching step to a total stretching ratio of 4.0 to 7.0 times. be. The high-strength polymetaphenylene isophthalamide fiber of the present invention is characterized in that 95 mol% or more of the polymer repeating units are metaphenylene isophthalamide units, and the intrinsic viscosity [η]f is within a specific range of 0.7 to 2.5. It is composed of polymetaphenylene isophthalamide-based polymer. It has a much larger molecular orientation than conventional polymetaphenylene isophthalamide fibers, that is, a molecular orientation with a birefringence of 0.18 to 0.22, and also has a high degree of crystallinity, which can be determined by X-ray method. 45 in terms of crystallinity
Within the range of ~55%. On the other hand, it has a smaller crystal size than conventional polymetaphenylene isophthalamide fibers, and the crystal size determined by X-ray diffraction is within the range of 35 to 45 Å. The polymer constituting the polymetaphenylene isophthalamide fiber of the present invention is preferably a polymetaphenylene isophthalamide homopolymer, and is 95 mol% or more, preferably 98 mol% or more of the polymer repeating units. is metaphenylene isophthalamide, and may be a polymer copolymerized with 5 mol % or less, preferably 2 mol % or less of the third component. If the content of the third component exceeds 5 mol %, the crystallinity of the fiber will decrease, and physical properties such as breaking strength and toughness will also deteriorate. Examples of the third component that can be copolymerized in a proportion of 5 mol % or less include terephthalic acid, paraphenylene diamine, metaxylylene diamine, and the like. The degree of polymerization of the polymetaphenylene isophthalamide polymer constituting the fiber is determined by the N
-Polymer concentration 0.5 in methyl-2-pyrrolidone
Intrinsic viscosity [η]f measured at 30°C after dissolving to give g/100ml is 0.7 to 2.5, preferably 1.2
~2.0. When [η]f is less than 0.7,
Even if the molecular orientation, crystallinity, crystal size, etc. of the fibers are adjusted as described above, the fibers do not have high breaking strength and toughness, and the object of the present invention cannot be achieved. On the other hand, if the intrinsic viscosity [η] of the polymer exceeds 2.5, the viscosity of the spinning dope will be abnormally high, and if you try to keep the viscosity of the spinning dope within the viscosity limit that allows spinning, the polymer concentration of the spinning dope will be reduced. It has to be made extremely small, making it impossible to spin with good productivity. The above polymer constituting the fiber may contain, if necessary,
It may contain various additives such as colorants, ultraviolet absorbers, light stabilizers, and flame retardants. The polymetaphenylene isophthalamide fibers of the present invention have a birefringence of 0.18 to 0.22, preferably 0.19 to 0.21, indicating that the fibers have a very high degree of molecular orientation. The fibers also have a significantly higher crystallinity than conventional polymetaphenylene isophthalamide fibers, i.e. 45-55%, preferably 48%.
It has a crystallinity of ~53 and also has a smaller crystal size compared to conventional polymetaphenylene isophthalamide fibers, i.e. 35-45 Å, preferably 38-43 Å. When the birefringence index is less than 0.18, the crystallinity of the fiber is 48
% or more, and the desired breaking strength, toughness, etc. cannot be obtained. On the other hand, the birefringence
When it exceeds 0.22, the crystallinity is greater than 55%,
The elongation of the fibers decreases and the fibers become brittle. Also,
If the degree of crystallinity is less than 45%, the fiber will not exhibit sufficient strength, and conversely, if the degree of crystallinity exceeds 55%, the elongation of the fiber will be low and the fiber will become brittle. Furthermore, if the crystal size is smaller than 35 Å, the division between the crystalline part and the amorphous part in the fiber becomes unclear, resulting in poor dimensional stability of the fiber, and the crystal size becomes smaller than 45 Å.
If it is larger, it becomes difficult for the crystals to align in the direction of the fiber axis inside the fiber, and the physical properties of the fiber deteriorate. In the polymetaphenylene isophthalamide fiber of the present invention, by making it highly oriented and highly crystalline and controlling the size of individual crystals to be small, the elongation of the fiber can be impaired. Without,
It is completely unexpected that the strength at break is improved by about 20% or more compared to conventional polymetaphenylene isophthalamide fibers, and the toughness expressed by silk factor is also increased. According to the research conducted by the present inventors, the polymetaphenylene isophthalamide fiber of the present invention usually has a degree of crystal orientation of 90 to 95%, and the degree of crystal orientation is also lower than that of conventional fibers. It turned out to be quite expensive. Further, the form of the polymetaphenylene isophthalamide fiber of the present invention may be either multifilament or staple fiber, and the fineness and cross-sectional shape are not limited, but the fineness per filament is generally in the range of 1 to 10 de. Yes, the cross-sectional shape is
It can be circular, oval, triangular, eyebrow-shaped, or any other shape. Due to the specific microstructure as described above, the polymetaphenylene isophthalamide fiber of the present invention has
It has a high breaking strength of 6.5 g/de or more, preferably 7.0 to 8.5 g/de. Despite having such a high breaking strength, the fiber of the present invention has a preferable elongation at break of 20 to 30%. Therefore, the silk factor, which is a measure of the amount of work it takes for the fiber to break, is 35 or higher, indicating great toughness. Furthermore, the fibers of the present invention have excellent fibrillation resistance and do not have the problem of fibrillation during use, unlike polyparaphenylene terephthalamide fibers. It also has good heat resistance, with a shrinkage rate of 7% or less at 300°C, and excellent dimensional stability against heat. In addition, in the fibers of the present invention, fibers made of a polymethaphenylene isophthalamide polymer in which 20% or more of all polymer ends are blocked with a monofunctional compound such as aniline can be held for a long time especially at high temperatures. In this case, the strength retention rate is also excellent. The high-strength polymetaphenylene isophthalamide fiber of the present invention as described above can be industrially produced by the method of the present invention comprising a series of steps described below. That is, first, in the spinning step, a polymethaphenylene isophthalamide system in which 95 mol% or more of the polymer repeating units is metaphenylene isophthalamide and has an intrinsic viscosity [η] of 0.7 to 2.5, preferably 1.2 to 2.0. A spinning dope in which a polymer is dissolved in an organic solvent is extruded from a spinneret having at least one spinning hole, and coagulated in a coagulation bath to form an end-drawn fiber. In this case, the spinning dope may be directly extruded into the coagulation bath, or may be once extruded into the air and then immediately introduced into the coagulation bath and coagulated. It is generally said that it is preferable to add an inorganic salt such as calcium chloride or lithium chloride to the spinning dope because it increases the dissolving power, but in the method of the present invention, it is preferable that the spinning dope does not substantially contain such an inorganic salt. If the spinning dope contains an inorganic salt, the operation of washing and removing the inorganic salt contained in the fiber after spinning is complicated, and the fiber manufacturing process becomes long and complicated. As the organic solvent used for preparing the spinning dope, polar amide solvents are suitable, and N-methyl-2-pyrrolidone, N,N'-dimethylformamide or N,N'-dimetalacetamide is particularly preferred. . The polymer concentration in the spinning dope varies depending on the intrinsic viscosity of the polymer, but generally
15-30% by weight is preferred. On the other hand, for the coagulation bath, an aqueous solution of an inorganic salt such as calcium chloride, magnesium chloride, zinc chloride, etc. is used. The temperature of the coagulation bath is preferably 60 to 100°C. Specific spinning conditions can be found, for example, in Japanese Patent Publication No. 48-17551,
It is described in detail in US Pat. No. 4,073,837 and the like. The undrawn fibers pulled out from the coagulation bath are then subjected to a first water washing step in which a part of the organic solvent contained in the fibers is removed to reduce the solvent content in the fibers to 15 to 30%.
Adjust to % by weight. In addition, the solvent content in the fiber as used in the present invention is a value expressed as a percentage of the weight of the organic solvent in the fiber relative to the weight of the fiber that does not contain any solvent. This first water washing step may be carried out in one stage using one washing bath, or may be carried out in two or more stages using two or more washing baths. In the first washing step, it is preferable that the washing bath contains 10 to 40% by weight of the same organic solvent as the organic solvent of the spinning dope, and the temperature of the washing bath in the first washing step is 20 to 40% by weight.
70°C is preferred. The fibers whose organic solvent content has been adjusted in the first water washing step described above are then drawn to a total draw ratio of 1.1 to 1.5 times in the first water bath drawing step. This first water bath stretching may be performed in one stage,
It may be done in two or more stages. In most cases, this first water bath drawing step also removes some of the organic solvent in the fiber, but if the organic solvent content is reduced to 15% during drawing,
It is necessary to adjust the drawing bath composition so as not to reduce the amount below the weight percent. For this reason, it is preferable that the stretching bath contains 3 to 30% by weight of the same organic solvent as the organic solvent in the dope. Further, the stretching bath temperature is suitably 50 to 95°C, preferably 60 to 90°C. The stretching ratio in the first water bath stretching was 1.1.
~1.5 times (if stretching is done in two or more stages, the total stretching ratio should be 1.1 to 1.5 times); if this stretching ratio is less than 1.1 times, the effect of this stretching process will be poor, and the final The crystal structure and molecular orientation of the drawn fibers thus obtained are insufficient, and the fibers cannot have the desired strength and toughness. Furthermore, if the stretching ratio exceeds 1.5 times, the flow of molecules takes precedence in the first water bath stretching step, resulting in fibers with poor orientation, resulting in poor effects of this stretching step. In a preferred first water bath drawing step, the fibers that have undergone the first water washing step are first drawn in a first bath (water bath) containing the same organic solvent as the organic solvent in the dope at a concentration of 10 to 30% by weight. 1.1-1.4 times at a temperature of 70-90°C in a second bath (water bath) containing the above-mentioned organic solvent in a concentration of 5-15% by weight and lower than that of the first bath. Stretching is performed such that the total stretching ratio in the primary water bath stretching step is 1.1 to 1.5 times. When such stretching conditions are adopted,
This is preferred because the primary water bath drawing can be carried out very smoothly and the finally obtained drawn fibers have particularly excellent physical properties. The fibers that have undergone the first water bath drawing process are then subjected to the second water bath drawing process.
The fibers are then sent to a water washing step where the organic solvent content in the fibers is reduced to less than 15% by weight. This second water washing step can also be carried out in one stage or in two or more stages. The organic solvent content in the fiber after the second water washing process is
If it is 15% by weight or more, the molecular orientation of the fibers will not improve in the subsequent secondary water bath drawing step, and crystallization will not proceed in the subsequent dry heat drawing, making it impossible to obtain fibers with desired physical properties. do not have. The secondary water washing step is carried out using one or more washing baths, but the washing bath may include only water,
Alternatively, a bath consisting of water containing the same organic solvent as in the dope at a concentration of 10% by weight or less is used. The temperature of the water washing bath is preferably 60 to 90°C. The fibers whose organic solvent content was adjusted to less than 15% by weight in the second water washing step are then subjected to at least one drawing bath to increase the amount by 1.1 times or more, preferably from 1.5 to 3.0 times, in the second water bath drawing step. The film is stretched in at least one stage. In the second water bath drawing step, part or all of the organic solvent remaining in the fibers during drawing is removed. As the stretching bath, water alone or water containing the same organic solvent as the organic solvent in the dope at a concentration of less than 10% by weight is used. The stretching bath temperature is preferably 90 to 100°C. After the second water bath stretching, it is preferable to further wash the fibers with water only to completely remove the residual solvent. The fibers thus subjected to the second water bath drawing and further washed with water if necessary are wound around a drying roller several times at, for example, 100 to 140°C, dried, and then subjected to dry heat drawing. In the dry heat drawing step, the fibers are drawn on a hot plate or in a heating chamber so that the total draw ratio after spinning is 4.0 to 7.0 times, preferably 4.5 to 6.5 times. The stretching temperature is preferably 300 to 450°C, and the stretching ratio in this dry heat stretching step is suitably 1.5 to 2.5 times. In addition, if the total stretching ratio is lower than 4.0 times, the breaking strength of the obtained fiber will be lower than 6.5 g/de,
Moreover, if it is higher than 7.0 times, fluff and yarn breakage will occur during stretching, which is not preferable. As mentioned above, the fibers immediately after spinning are subjected to the first water washing process, the first water bath drawing process, the second water bath drawing process, the second water bath drawing process (-final water washing process), respectively, under specific conditions.
Drying process - Drying stretching process is carried out continuously or batchwise, and if necessary, heat treatment, crimping,
By performing other finishing processes, the high-strength polymetaphenylene isophthalamide fiber of the present invention can be manufactured with good productivity. (Effects of the Invention) The polymethaphenylene isophthalamide fiber of the present invention as described above has a strength approximately 20% higher than that of conventional polymethaphenylene isophthalamide fibers, and also has sufficient elongation. It is a rubber reinforcing material that conventionally could not be used with polymetaphenylene isophthalamide fiber because of its excellent heat resistance.
It can now be used in fields such as resin reinforcement materials and felt base materials for bag filters, and it can also be used to manufacture products with similar strength in fields where conventional polymetaphenylene isophthalamide fibers were used. Since it is possible to reduce the amount of fiber required for use, the product can be made lighter, shorter, etc. Furthermore, the polymethaphenylene isophthalamide fiber of the present invention not only has high initial strength, but also has a strength retention rate at high temperatures equivalent to that of conventional polymethaphenylene isophthalamide fiber, so it can be used in bag filters, etc. When used in products that are constantly used at high temperatures, it also has the effect of extending the life of the product. Further, according to the manufacturing method of the present invention, the above-mentioned high-strength polymetaphenylene isophthalamide fiber can be efficiently manufactured in a stable process condition. (Method for measuring each index) Next, a method for measuring each index according to the present invention will be explained. (a) Intrinsic viscosity ([η], [η]f) Intrinsic viscosity is a measure of the molecular weight of a polymer, and in the present invention, 0.5 g of polymer or fiber is dissolved in 100 ml of anhydrous N-methyl-2-pyrrolidone. It is expressed as the intrinsic viscosity of the solution at 30°C. Note that here, the intrinsic viscosity of the raw material polymer is [η], and the intrinsic viscosity after being made into fibers is [η]f. (b) Crystallinity: Based on normal X-ray measurement method. However, the calculation of crystalline parts and amorphous parts is as follows. (i) The range of 2θ shall be from 12° to 32°. (ii) Draw a straight line from the amorphous part 2θ=17° to 2θ=30°,
The curve consisting of this line segment and the meridional diffraction curve of 2θ<17°, 2θ>30° is the amorphous scattering curve, and the portion (C) between this and the non-oriented approximate curve is the contribution of the crystal,
The portion (A) between this and the air scattering curve is assumed to be the amorphous contribution. Crystallinity = C/T (1-12.7/100) However, T = A + C (c) Crystal size Rigaku Denki Co., Ltd.'s X-ray generator (Cat. No. 4032A2),
A wide-angle diffractometer and counting circuit unit are used. The sample was mounted on a 4.5 cm long holder so that the width density was approximately 2.2 g/cm, and the sample was placed against the scan axis of the diffractometer.
Make the stretching direction (length direction) vertical. Uses Cu-Kα radiation (λ = 1.5418 Å). The crystal size D is calculated in Å by the following formula. D=0.94λ/(B-b)cosθ (This formula is widely described in books on polymer X-ray diffraction.) 0.94 is called the Schierer constant, and B is the measurement peak expressed in radians (2θ = 27.3℃) half-value width. b is the device broadening constant (in radians), which is 0.0017rad (approx.
0.1℃). The following procedure is used to determine B from an X-ray diffraction chart. If there are two overlapping main peaks on the equator, each peak is separated by assuming that each peak has a Gaussian curve shape. Next, a curve obtained from the meridional diffraction curve, which is a dotted line of the heights of areas with no peaks, is adopted as the baseline, and a straight line is drawn parallel to the baseline from the midpoint of the peak apex and the baseline to peak at the measured peak. Find the width (half value) of the intersection point in radians, and let this be B. The range of D specified in the present invention differs between when two main peaks overlap and when only one main peak is substantially observed. If the two main peaks overlap and the smaller 2θ peak is extracted and measured as a Gaussian curve, D is
It was found that it should be 55 Å or less, and only one main peak was observed, and when D was calculated from that peak, it should be 33 Å or less. The reason why the range of D in the two cases is different is probably because
Even though only one peak is actually observed, it should originally consist of two peaks, but due to the copolymerization effect, it will be observed as if it were only one peak. The detailed measurement conditions are as follows. Voltage 50kv Current 80mA Time constant 1sec Sweep speed 2°/min Chart speed 2cm/min Irradiation diameter on sample surface 2.8mmφ (d) Crystal orientation The same X-ray generator, wide-angle diffractometer, and A counting circuit unit will be used, but a fiber rotating sample stand will be newly installed that can measure in the azimuthal direction. The same applies to the sample density of the sample. The fiber is rotated in the azimuth direction while maintaining the 2θ value with the maximum peak on the equator line to obtain the oriented diffraction peak. It is easy to find the baseline, and from the midpoint of the perpendicular line drawn from the peak to this baseline, draw a straight line parallel to the baseline and find the point of intersection with the shoulder of the peak. Assuming that the length (half width at half maximum) of the line segment formed by this intersection is H (degrees), the degree of orientation f is determined by the following equation. f=180-H/180×100 (%) This method is introduced in general literature on polymer X-ray diffraction. Note that the other measurement conditions are the same as in the case of crystal size. (e) Strength and elongation at break According to JIS L-1015 (1983) "Test Method for Chemical Fiber Staples". (f) Silk factor Calculated using the following formula. Silk factor = strength (g/de) x √ elongation (%) (g) Organic solvent content in fiber Based on the method for measuring the residual solvent amount S described in column 4 of Japanese Patent Publication No. 10173/1983. (f) Organic solvent concentration in washing bath and drawing bath The organic solvent content in fibers can be measured by the following procedure. (1) Collect 5gr of yarn and weigh it accurately. This weight
Let it be W ₁ . (2) 60℃ 1 with standard methanol 1 with known moisture content
Extract samples for days. (3) Measure the water content of the extracted methanol using the Karl Fischer method, and let the extracted water content be _W2 . (4) Evaporate the extracted methanol to dryness (carry out at gradually higher temperatures, finally at 300°C, for a total of 5
time). (5) Weigh the residue and take this weight as W ₃ . (6) Dry the extracted sample at 130°C for 1 hour and weigh it. Let this weight be W ₄ . (7) Calculate the residual catalyst amount B using the following formula. B=W ₁ −W ₂ −W ₃ −W ₄ /W ₄ ×100 (%) (Example) Next, examples and comparative examples of the present invention will be described in detail.
The present invention is not limited to these in any way. Example 1 Isophthalic acid chloride (mp44.5-45.0℃)
Dissolve 14.2 g in 100 ml of tetrahydrofuran dehydrated with metallic sodium, put this in a Waring blender with three rotating blades, and blend at a rate of about 300 m/min.
A cloudy emulsion is obtained by gradually adding a solution of 7.41 g of metaphenylenediamine (mp 62.0 to 63.0° C.) dissolved in 100 ml of dehydrated tetrahydrofuran as a trickle while stirring with rotation. After stirring for about 5 minutes, 14.8 g of soda carbonate and 28.0 g of salt were added to the stirring speed of about 1500 revolutions per minute.
Immediately add the aqueous solution dissolved in 300 ml of water and continue stirring for about 5 minutes. The viscosity of the reaction system increases after a few seconds and a white suspension is obtained again. A transparent aqueous solution layer was separated by standing, which was removed and filtered to obtain 16.4 g (yield 98%) of a white polymer.Polymetaphenylene isophthalamide with an intrinsic viscosity [η] of 1.45. A spinning dope was prepared by dissolving the polymer in a solvent consisting of N-methyl-2-pyrrolidone at a concentration of 20.5% by weight.
According to the wet spinning method described in the publication, the pore diameter is 0.07 mm.
The fibers were spun from a spinneret with 10,000 spinning holes into a coagulation bath consisting of an aqueous calcium chloride solution with a calcium chloride concentration of 45% and a temperature of 90°C. The coagulated undrawn fibers contained 45% by weight of solvent upon withdrawal from the coagulation bath. This undrawn fiber was washed with water for 30 minutes in the first water washing process.
The solvent content in the fiber was reduced to 25% by weight by passing it through a 30°C water bath containing % by weight of solvent. Next, this fiber was drawn in two stages under the conditions shown in Table 1 in the first water bath drawing step.

【表】このように第１次水浴延伸を行つた繊維を、第
２次水洗工程において50℃の水浴中で水洗して溶
媒含有率を10重量％まで低下させた。引続き、第
２次水浴延伸工程において90℃の水浴中で2.1倍
に延伸した後、120℃で乾燥し、次の乾熱延伸工
程において350℃の熱板上で1.7倍に延伸した。紡
糸後の全延伸倍率は4.7倍であつた。この実験結果を後掲の第２表に示す。比較例１従来の方法によりポリメタフエニレンイソフタ
ラミド繊維を製造した。即ち、固有粘度［η］が
1.35のポリメタフエニレンイソフタラミドを用い
て実施例１に準じて湿式紡糸し、凝固浴上りの未
延伸繊維を60℃の水浴中で水洗して溶媒含有率を
８重量％まで低下せしめた後、95℃の水浴中で
2.4倍に延伸し、130℃で乾燥後350℃の熱板上で
1.75倍に延伸した。この結果を第２表に示す。[Table] In the second water washing step, the fibers subjected to the first water bath drawing were washed in a water bath at 50° C. to reduce the solvent content to 10% by weight. Subsequently, in a second water bath stretching step, the film was stretched to 2.1 times in a water bath at 90° C., dried at 120° C., and then stretched to 1.7 times on a hot plate at 350° C. in the next dry heat stretching step. The total stretching ratio after spinning was 4.7 times. The results of this experiment are shown in Table 2 below. Comparative Example 1 Polymetaphenylene isophthalamide fibers were produced by a conventional method. That is, the intrinsic viscosity [η] is
Wet spinning was performed according to Example 1 using polymetaphenylene isophthalamide of 1.35, and the undrawn fibers after the coagulation bath were washed with water in a 60°C water bath to reduce the solvent content to 8% by weight. Afterwards, in a 95℃ water bath.
Stretched 2.4 times, dried at 130℃, then placed on a hot plate at 350℃.
It was stretched 1.75 times. The results are shown in Table 2.

【表】第２表より明らかなごとく、従来のポリメタフ
エニレンイソフタラミド繊維の強度は高々5.5
ｇ／de程度であるのに対し、本発明の繊維は、
7.2ｇ／deもの高い破断強度を有し、従つて、繊
維の破断に至るまでの仕事量を表わすシルクフア
クターも39.4と、きわめて高い値を示している。また、実施例１により得られた本発明の繊維
を、バツグフイルター用フエルトの基布の基材と
して用いたところ、従来の繊維を用いたものに比
べ製品寿命が著しく延長することが確認された。実施例２実施例１と同様に界面重合法により固有粘度
［η］1.35のポリメタフエニレンイソフタラミド
重合体を製造し、該重合体をＮ−メチル−２−ピ
ロリドンからなる溶媒に溶解しポリマー濃度22重
量％の紡糸ドープを調製した。このドープを特公昭48−17551号公報に記載の
湿式紡糸法に従つて孔径0.08mmの紡糸孔を6000有
する紡糸口金から塩化カルシウム濃度43重量％、
温度95℃の塩化カルシウム水溶液からなる凝固浴
中へ湿式紡糸した。凝固浴上りの未延伸繊度の溶
媒含有率は43重量％であつた。この繊維を第１次
水洗工程において30重量％の溶媒を含む40℃の水
洗浴で水洗し繊維中の溶媒含有率を23重量％に低
下させた。次に、この繊維を第１次水浴延伸工程で第３表
に示す条件で２段延伸した。[Table] As is clear from Table 2, the strength of conventional polymetaphenylene isophthalamide fibers is at most 5.5.
g/de, whereas the fiber of the present invention has
It has a breaking strength as high as 7.2 g/de, and its silk factor, which represents the amount of work required to break the fiber, is also extremely high at 39.4. Furthermore, when the fiber of the present invention obtained in Example 1 was used as a base material for a felt fabric for bag filters, it was confirmed that the product life was significantly extended compared to those using conventional fibers. . Example 2 A polymetaphenylene isophthalamide polymer having an intrinsic viscosity [η] of 1.35 was produced by the interfacial polymerization method in the same manner as in Example 1, and the polymer was dissolved in a solvent consisting of N-methyl-2-pyrrolidone. A spinning dope with a polymer concentration of 22% by weight was prepared. This dope was passed through a spinneret having 6,000 spinning holes with a pore diameter of 0.08 mm according to the wet spinning method described in Japanese Patent Publication No. 17551/1983, with a calcium chloride concentration of 43% by weight.
Wet spinning was carried out into a coagulation bath consisting of an aqueous calcium chloride solution at a temperature of 95°C. The solvent content of the undrawn fineness after the coagulation bath was 43% by weight. In the first water washing step, this fiber was washed in a 40°C water washing bath containing 30% by weight of solvent to reduce the solvent content in the fiber to 23% by weight. Next, this fiber was drawn in two stages under the conditions shown in Table 3 in a first water bath drawing step.

【表】このように２段延伸した繊維を常温の水中で洗
浄して繊維中の溶媒含有率を12重量％以下まで低
下させた後、第２次水浴延伸工程に入り、90℃の
水浴中で2.2倍に延伸した。延伸後の繊維はさら
に90℃の水中で洗浄した後、120℃で乾燥し、引
続き、355℃の熱板上で1.7倍に延伸した。紡糸後
の全延伸倍率は4.9倍であつた。この実験の結果は後掲の第５表に示す。実施例３〜５、比較例３次の第４表に示す条件以外は実施例２と同様に
してポリメタフエニレンイソフタラミド繊維を製
造した。これらの実験の結果は後掲の第５表に示す。[Table] After washing the fibers drawn in two stages in this way in water at room temperature to reduce the solvent content in the fibers to 12% by weight or less, the fibers are drawn in a second water bath in a water bath at 90°C. It was stretched 2.2 times. The stretched fibers were further washed in water at 90°C, dried at 120°C, and then stretched 1.7 times on a hot plate at 355°C. The total stretching ratio after spinning was 4.9 times. The results of this experiment are shown in Table 5 below. Examples 3 to 5, Comparative Example 3 Polymethaphenylene isophthalamide fibers were produced in the same manner as in Example 2 except for the conditions shown in Table 4 below. The results of these experiments are shown in Table 5 below.

【表】 (注) ＊印は延伸を行わず水洗のみ
＊＊印は延伸浴中にCaCl_２も含む
実施例６純度99.95％のイソフタル酸クロライド（IPC）
213.18Kgを脱水したテトラヒドロフラン（THF）
（水分100ppm）750に溶解し、これを攪拌機、
冷却コイル、冷却ジヤケツトを有する容量２m³の
反応槽に入れ、毎分300回転の攪拌を行いながら
−22℃迄冷却した。一方、攪拌機、冷却コイル、
冷却ジヤケツトを有する容量１m³の溶解槽で、純
度99.93％のメタフエニレンジアミン（MPDA）
113.55Kgを750のTHF（水分率100ppm）に溶解
し−22℃迄冷却した。冷却されたMPDAのTHF
溶液を4.3／分の添加速度で多数のノズル口よ
り粒径0.1mm以下の噴霧状でIPCのTHF溶液に200
分間で攪拌下に添加すると白濁した乳化液が得ら
れ、このときの反応槽の内温は−15℃であつた。
添加終了後約５分間攪拌を継続した。高速攪拌機を有する容量５m³の反応槽に炭酸ソ
ーダ156Kgを水1750に溶解した水溶液を加え毎
分1700回転に攪拌後速かに前記の白濁した乳化液
を加え約５分間攪拌を継続した。反応系は数分後
に粘が増大し、再び低下、白色の懸濁液が得られ
た。これを濾過することにより白色粉末を得、濾
別水洗後乾燥し249.4Kg（収率99.8％）のポリメ
タフエニレンイソフタラミドの白色重合体が得ら
れた。この重合体の固有粘度［η］は2.0であつた。この重合体は、高速液体クロマトグラフイで分
子量分布を測定すると、高分子量物のピーク
（Ａ）が著しく大となり96.9％を占めるのに対し、
低分子量物（Ｂピーク）は実質的に０であり、ま
たオリゴマー（Ｃピーク）も著しく減少しており
3.1％であつた。即ちこの重合体は特に分子量分
布がシヤープになつていることが確認された。この重合体をＮ−メチル−２−ピロリドン
（NMP）に溶解して濃度18重量％の紡糸ドープ
となし、実施例２と同様に湿式紡糸した。凝固浴上りの未延伸繊維は、45重量％の溶媒を
含んでいた。この未延伸繊維を30重量％の溶媒を
含む30℃の水浴で水洗し、繊維中の溶媒含有率を
24重量％とした。次に、この繊維を第１次水浴延伸工程におい
て、次の条件で２段延伸した。即ち、第１段で20
％の溶媒を含む45℃の水浴中で1.1倍に延伸し、
続いて第２段で15重量％の溶媒を含む50℃の水浴
中で1.2倍に延伸した。このように延伸した繊維
は、次いで70℃の水で洗浄し繊維中の溶媒含有率
を14重量％まで低下させた後、第２次水浴延伸工
程において、次の条件で２段延伸した。即ち、第
１段で80℃の水浴中で2.1倍に延伸し、続いて第
２段で90℃の水浴中で1.1倍に延伸した。かくして水浴延伸した繊維は、130℃で乾燥後、
355℃の熱板上で1.70倍に乾熱処理した。この実験の結果を第５表に示す。[Table] (Note) *marked means no stretching, just washing with water
**marked is an example in which CaCl ₂ was also included in the drawing bath 6 Isophthalic acid chloride (IPC) with a purity of 99.95%
213.18Kg of dehydrated tetrahydrofuran (THF)
(moisture 100ppm) Dissolve in 750, mix this with a stirrer,
The mixture was placed in a reaction tank with a capacity of 2 m ³ equipped with a cooling coil and a cooling jacket, and cooled to -22°C while stirring at 300 revolutions per minute. Meanwhile, stirrer, cooling coil,
Metaphenylenediamine (MPDA) with a purity of 99.93% in a dissolution tank with a capacity of 1 m ³ with a cooling jacket.
113.55 kg was dissolved in 750 THF (moisture content 100 ppm) and cooled to -22°C. Cooled MPDA THF
The solution was sprayed into the THF solution of IPC with a particle size of 0.1 mm or less from multiple nozzle ports at an addition rate of 4.3/min.
When the mixture was added for 1 minute with stirring, a cloudy emulsion was obtained, and the internal temperature of the reaction tank at this time was -15°C.
Stirring was continued for approximately 5 minutes after the addition was complete. An aqueous solution of 156 kg of soda carbonate dissolved in 1,750 rpm of water was added to a reaction tank with a capacity of 5 m ³ equipped with a high-speed stirrer, and the mixture was stirred at 1,700 revolutions per minute.Then, the cloudy emulsion was quickly added and stirring was continued for about 5 minutes. The viscosity of the reaction system increased after a few minutes and then decreased again to yield a white suspension. This was filtered to obtain a white powder, which was separated by filtration, washed with water, and dried to obtain 249.4 kg (yield: 99.8%) of a white polymer of polymetaphenylene isophthalamide. The intrinsic viscosity [η] of this polymer was 2.0. When the molecular weight distribution of this polymer was measured using high performance liquid chromatography, the peak (A) of the high molecular weight product was extremely large, accounting for 96.9%;
Low molecular weight substances (B peak) are virtually 0, and oligomers (C peak) are also significantly reduced.
It was 3.1%. That is, it was confirmed that this polymer had a particularly sharp molecular weight distribution. This polymer was dissolved in N-methyl-2-pyrrolidone (NMP) to prepare a spinning dope having a concentration of 18% by weight, and wet spinning was carried out in the same manner as in Example 2. The undrawn fibers after the coagulation bath contained 45% by weight of solvent. The undrawn fibers were washed in a 30°C water bath containing 30% by weight of solvent to reduce the solvent content in the fibers.
The content was 24% by weight. Next, this fiber was drawn in two stages under the following conditions in the first water bath drawing step. That is, 20 in the first stage
Stretched 1.1x in a 45 °C water bath containing % solvent;
Subsequently, in the second stage, the film was stretched 1.2 times in a 50°C water bath containing 15% by weight of solvent. The thus drawn fibers were then washed with water at 70° C. to reduce the solvent content in the fibers to 14% by weight, and then subjected to two-step drawing under the following conditions in a second water bath drawing step. That is, in the first stage it was stretched 2.1 times in a water bath at 80°C, and then in the second stage it was stretched 1.1 times in a water bath at 90°C. After drying the fibers thus drawn in a water bath at 130°C,
Dry heat treatment was performed on a hot plate at 355°C to increase the temperature by 1.70 times. The results of this experiment are shown in Table 5.

【表】実施例７純度99.95％イソフタル酸クロライド（IPC）
213.18Kgを脱水したテトラヒドロフラン（THF）
（水分率100ppm）750に溶解し、これを攪拌機、
冷却コイル、冷却ジヤケツトを有する容量２m³の
反応槽に入れ、毎分約300回転の攪拌を行いなが
ら−10℃迄冷却した。他方の攪拌機、冷却コイ
ル、冷却ジヤケツトを有する容量１m³の溶解槽で
純度99.93％メタフエニレンジアミン（MPDA）
を750の脱水したTHF（水分率100ppm）に溶解
し−15℃ま迄冷却した。冷却されたMPDAの
THF溶液を8.5／分の添加速度でノズル口より
粒径0.1mm以下の噴霧状でIPCのTHF溶液中に120
分間で攪拌下に添加した。このときの反応槽の内
温は−４℃であつた。添加終了後約10分後に450
のアニリンを添加し攪拌し、白濁した乳化液を
得た。これと別に高速攪拌機を有する容量５m³の
反応槽に炭酸ソーダ195Kgを水1750に溶解した
水溶液を加え、毎分1700回転に攪拌した。アニリ
ン添加終了から15分後の白濁した乳化液を炭酸ソ
ーダ水溶液中に加え、約５分間攪拌を継続した。
反応系は数秒後に粘度が増大し、再び低下白色の
懸濁系が得られた。濾過により白色粉末を濾別
し、水洗後乾燥し、249.2Kg（収率99.7％）の末
端封鎖したポリメタフエニレンイソフタラミドの
白色重合体が得られた。この重合体の固有粘度
［η］は1.32であつた。また、重合体中の全末端
基量の26％がアニリンにより封鎖されており、オ
リゴマー量は4.1重量％であつた。固有粘度［η］の平均値は1.32であり、そのバ
ラツキ（α）は0.03であつた。このことは固有粘
度のバラツキが非常に小さいことを示している。この重合体を用いて実施例２と同様にして繊維
を製造した。得られた繊維は、単糸繊度2de、複屈折率0.20、
結晶化度51％、結晶サイズ39Å、結晶配向度93％
であり、破断強度は7.8ｇ／de、破断伸度は26％
であつて39.8のシルクフアクターを示した。ま
た、300℃における収縮率は5.8％であつた。この繊維を300℃で乾熱下で20時間保持したと
きの強度維持率は94％であつた。[Table] Example 7 99.95% purity isophthalic acid chloride (IPC)
213.18Kg of dehydrated tetrahydrofuran (THF)
(moisture content 100ppm) 750, mix this with a stirrer,
The mixture was placed in a reaction tank with a capacity of 2 m ³ equipped with a cooling coil and a cooling jacket, and cooled to -10°C while stirring at about 300 revolutions per minute. Metaphenylenediamine (MPDA) with a purity of 99.93% in a dissolution tank with a capacity of 1 m ³ with a stirrer, a cooling coil and a cooling jacket on the other hand.
was dissolved in 750% dehydrated THF (moisture content 100 ppm) and cooled to -15°C. cooled MPDA
The THF solution was sprayed from the nozzle opening at a rate of 8.5/min with a particle size of 0.1 mm or less into the THF solution of IPC.
The mixture was added under stirring for a few minutes. The internal temperature of the reaction tank at this time was -4°C. 450 approximately 10 minutes after completion of addition.
of aniline was added and stirred to obtain a cloudy emulsion. Separately, an aqueous solution of 195 kg of soda carbonate dissolved in 1,750 kg of water was added to a 5 m ³ reaction tank equipped with a high-speed stirrer, and the mixture was stirred at 1,700 revolutions per minute. Fifteen minutes after the completion of the addition of aniline, the cloudy emulsion was added to the aqueous sodium carbonate solution, and stirring was continued for about 5 minutes.
The viscosity of the reaction system increased after a few seconds and a white suspension was obtained again. A white powder was separated by filtration, washed with water, and dried to obtain 249.2 kg (yield: 99.7%) of a white polymer of end-capped polymetaphenylene isophthalamide. The intrinsic viscosity [η] of this polymer was 1.32. Further, 26% of the total amount of terminal groups in the polymer was blocked by aniline, and the amount of oligomer was 4.1% by weight. The average value of intrinsic viscosity [η] was 1.32, and its variation (α) was 0.03. This shows that the variation in intrinsic viscosity is very small. Fibers were produced in the same manner as in Example 2 using this polymer. The obtained fiber has a single yarn fineness of 2de, a birefringence index of 0.20,
Crystallinity 51%, crystal size 39Å, crystal orientation 93%
The breaking strength is 7.8g/de and the breaking elongation is 26%.
It showed a silk factor of 39.8. Furthermore, the shrinkage rate at 300°C was 5.8%. When this fiber was kept under dry heat at 300°C for 20 hours, the strength retention rate was 94%.

Claims

【特許請求の範囲】１ポリマー繰返し単位の少なくとも95モル％が
メタフエニレンイソフタラミドからなりかつポリ
マー濃度0.5ｇ／100mlの無水Ｎ−メチル−２−ピ
ロリドン溶液にて30℃の温度で測定した固有粘度
［η］ｆが0.7〜2.5であるポリメタフエニレンイ
ソフタラミド系重合体からなる繊維において、複
屈折率が0.18〜0.22、結晶化度が45〜55％、結晶
サイズが35〜45Åであることを特徴とする破断強
度6.5ｇ／de以上、シルクフアクター35以上の高
強力ポリメタフエニレンイソフタラミド系繊維。２結晶配向度が90〜95％である特許請求の範囲
第１項記載の高強力ポリメタフエニレンイソフタ
ラミド系繊維。３破断時の強度が7.0ｇ／de以上である特許請
求の範囲第１項記載の高強力ポリメタフエニレン
イソフタラミド系繊維。４破断時の伸度が20〜30％である特許請求の範
囲第１項記載の高強力ポリメタフエニレンイソフ
タラミド系繊維。５ポリマー繰返し単位の少なくとも95モル％が
メタフエニレンイソフタラミドからなりかつポリ
マー濃度0.5ｇ／100mlの無水Ｎ−メチル−２−ピ
ロリドン溶液にて30℃の温度で測定した固有粘度
［η］が0.7〜2.5であるポリメタフエニレンイソ
フタラミド系重合体を、有機溶媒に溶解して紡糸
ドープとなし、該紡糸ドープを塩化カルシウムを
含む水性凝固浴中に押出し、水洗、湿潤延伸、乾
燥、乾熱延伸してポリメタフエニレンイソフタラ
ミド系繊維を製造する方法において、紡糸して得
た未延伸繊維を第１次水洗工程に賦して繊維中の
有機溶媒含有率を15〜30重量％に調整し、次いで
第１次水浴延伸工程に賦して繊維中の有機溶媒含
有率が15〜30重量％の状態において少なくとも１
段で1.1〜1.5倍に延伸し、引続き第２次水洗工程
に賦して繊維中の有機溶媒含有率を15重量％未満
に調整した後、第２次水浴延伸工程に賦して少く
とも１段にて1.1倍以上に延伸し、次いで乾燥し、
しかる後乾燥延伸工程に賦して全延伸倍率が4.0
〜7.0倍となるように延伸することを特徴とする
高強力ポリメタフエニレンイソフタラミド系繊維
の製造方法。６有機溶媒が、Ｎ−メチル−２−ピロリドン、
Ｎ，N′−ジメチルアセトアミド及びＮ，N′−ジ
メチルホルムアミドからなる群から選ばれた少く
とも１種の溶媒である特許請求の範囲第５項記載
の製造方法。７第１次水洗工程において、湿式紡糸直後の未
延伸繊維を紡糸ドープ中の有機溶媒と同じ有機溶
媒を10〜40重量％の濃度で含む少くとも１つの水
浴にて水洗する特許請求の範囲第５項記載の製造
方法。８第１次水洗工程において、水洗浴の温度を20
〜70℃とする特許請求の範囲第５項又は第７項記
載の製造方法。９第１次水浴延伸工程において、延伸と同時に
繊維中に含まれる有機溶媒の一部を除去する特許
請求の範囲第５項記載の製造方法。１０第１次水浴延伸工程において、繊維を50〜
95℃の温度で延伸する特許請求の範囲第５項記載
の製造方法。１１第１次水浴延伸工程において、少くとも１
つの延伸浴中に、紡糸ドープ中の有機溶媒と同じ
有機溶媒を３〜30重量％の濃度で含有させる特許
請求の範囲第５項又は第１０項記載の製造方法。１２第１次水浴延伸工程において、有機溶媒濃
度が10〜30重量％の第１浴にて50〜70℃の温度で
1.1〜1.4倍に第１段延伸し、次いで有機溶媒濃度
が５〜15重量％であつてかつ第１浴の濃度よりも
低い第２浴にて70〜90℃の温度で第１次水浴延伸
工程の全延伸倍率が1.1〜1.5となる倍率で延伸す
る特許請求の範囲第５項、第１０項又は第１１項
記載の製造方法。１３第２次水洗工程において、繊維を少くとも
１つの水浴中を通して繊維中の有機溶媒含有率を
15重量％未満に調整する特許請求の範囲第５項記
載の製造方法。１４第２次水洗工程において、繊維を60〜100
℃の温度で水洗する特許請求の範囲第５項又は第
１３項記載の製造方法。１５第２次水浴延伸工程において、繊維を少く
とも１段で1.5〜3.0倍に延伸する特許請求の範囲
第５項記載の製造方法。１６第２次水浴延伸工程において、延伸と同時
に繊維中に残留する有機溶媒の少くとも一部を除
去する特許請求の範囲第５項又は第１５項記載の
製造方法。１７第２次水浴延伸工程において、繊維を90〜
100℃の温度で延伸する特許請求の範囲第５項、
第１５項又は第１６項記載の製造方法。１８乾熱延伸工程において、繊維を300〜400℃
の温度で延伸する特許請求の範囲第５項記載の製
造方法。１９乾熱延伸工程において、繊維を1.5〜2.5倍
に延伸する特許請求の範囲第５項又は第１８項記
載の製造方法。２０第２次水浴延伸工程の後に、繊維を少くと
も１回水洗する特許請求の範囲第１５項記載の製
造方法。[Scope of Claims] 1. At least 95 mol% of the polymer repeating units consist of metaphenylene isophthalamide and the polymer concentration is 0.5 g/100 ml as measured in an anhydrous N-methyl-2-pyrrolidone solution at a temperature of 30°C. A fiber made of a polymetaphenylene isophthalamide polymer with an intrinsic viscosity [η]f of 0.7 to 2.5, a birefringence of 0.18 to 0.22, a crystallinity of 45 to 55%, and a crystal size of 35 to 45 Å. A high-strength polymetaphenylene isophthalamide fiber with a breaking strength of 6.5 g/de or more and a silk factor of 35 or more. 2. The high-strength polymetaphenylene isophthalamide fiber according to claim 1, which has a degree of crystal orientation of 90 to 95%. 3. The high-strength polymetaphenylene isophthalamide fiber according to claim 1, which has a strength at break of 7.0 g/de or more. 4. The high-strength polymetaphenylene isophthalamide fiber according to claim 1, which has an elongation at break of 20 to 30%. 5 At least 95 mol% of the polymer repeating units consist of metaphenylene isophthalamide and the intrinsic viscosity [η] measured in an anhydrous N-methyl-2-pyrrolidone solution with a polymer concentration of 0.5 g/100 ml at a temperature of 30°C is 0.7 to 2.5 is dissolved in an organic solvent to make a spinning dope, the spinning dope is extruded into an aqueous coagulation bath containing calcium chloride, washed with water, wet stretched, dried, In a method for producing polymetaphenylene isophthalamide fibers by dry heat drawing, the undrawn fibers obtained by spinning are subjected to a first water washing step to reduce the organic solvent content in the fibers to 15 to 30% by weight. %, and then added to the first water bath stretching step to obtain at least 1
The fibers are stretched by 1.1 to 1.5 times in a step, and then subjected to a second water washing step to adjust the organic solvent content in the fibers to less than 15% by weight, and then subjected to a second water bath drawing step to obtain at least 1. Stretched to 1.1 times or more in stages, then dried,
After that, it is added to the dry stretching process and the total stretching ratio is 4.0.
A method for producing a high-strength polymetaphenylene isophthalamide fiber, which comprises stretching the fiber by a factor of ~7.0. 6 The organic solvent is N-methyl-2-pyrrolidone,
6. The method of claim 5, wherein the solvent is at least one solvent selected from the group consisting of N,N'-dimethylacetamide and N,N'-dimethylformamide. 7. In the first water washing step, the undrawn fibers immediately after wet spinning are washed in at least one water bath containing the same organic solvent as the organic solvent in the spinning dope at a concentration of 10 to 40% by weight. The manufacturing method described in Section 5. 8 In the first water washing process, the temperature of the water washing bath was set to 20°C.
The manufacturing method according to claim 5 or 7, wherein the temperature is 70°C. 9. The manufacturing method according to claim 5, wherein in the first water bath stretching step, part of the organic solvent contained in the fiber is removed simultaneously with the stretching. 10 In the first water bath drawing process, the fibers are
The manufacturing method according to claim 5, which stretches at a temperature of 95°C. 11 In the first water bath stretching step, at least 1
11. The manufacturing method according to claim 5 or 10, wherein the same organic solvent as the organic solvent in the spinning dope is contained in one drawing bath at a concentration of 3 to 30% by weight. 12 In the first water bath stretching step, at a temperature of 50 to 70°C in a first bath with an organic solvent concentration of 10 to 30% by weight.
First stage stretching to 1.1 to 1.4 times, followed by first water bath stretching at a temperature of 70 to 90°C in a second bath with an organic solvent concentration of 5 to 15% by weight and lower than that of the first bath. 12. The manufacturing method according to claim 5, 10 or 11, wherein the process is stretched at a total stretching ratio of 1.1 to 1.5. 13 In the second water washing step, the fibers are passed through at least one water bath to reduce the organic solvent content in the fibers.
The manufacturing method according to claim 5, wherein the content is adjusted to less than 15% by weight. 14 In the second washing process, the fibers are
The manufacturing method according to claim 5 or 13, which comprises washing with water at a temperature of °C. 15. The manufacturing method according to claim 5, wherein in the second water bath drawing step, the fibers are drawn 1.5 to 3.0 times in at least one stage. 16. The manufacturing method according to claim 5 or 15, wherein in the second water bath stretching step, at least a part of the organic solvent remaining in the fiber is removed simultaneously with the stretching. 17 In the second water bath drawing process, the fibers are
Claim 5, stretching at a temperature of 100°C;
The manufacturing method according to item 15 or 16. 18 In the dry heat drawing process, the fiber is heated to 300 to 400℃
6. The manufacturing method according to claim 5, wherein the stretching is performed at a temperature of . 19. The manufacturing method according to claim 5 or 18, wherein the fiber is stretched 1.5 to 2.5 times in the dry heat stretching step. 20. The manufacturing method according to claim 15, wherein the fibers are washed with water at least once after the second water bath drawing step.